The present invention relates to a pneumatic tire, more particularly to a tread groove structure capable of improving stone-entrapment and noise performance without sacrificing wet performance.
It is well known to be effective for improving wet performance of a pneumatic tire to provide wide circumferential grooves in the tread portion. Such a wide tread groove is however very liable to trap small objects such as gravel stones therein. In the case of heavy duty tires having very rigid tread portions, small objects entrapped deep in a tread groove are hard to self-eject. As a result, the groove bottom and inner structure of the tread portion are liable to be injured by the entrapped objects.
On the other hand, in the case of a wide circumferential groove, an air column formed in the circumferential groove in the ground contacting patch is liable to resonate during running and the noise performance of the tire is deteriorated.
If the groove width is decreased, these problems may be solved, but as the drainage is decreased, deterioration of the wet performance is inevitable.